Surveillance of schistosomiasis at a national surveillance site in the Dantu District in 2009.

Objective To analyze schistosomiasis trends and changes in Sanzhou Village,Dantu District,a national schistosomiasis surveillance site,in order to assess the effects of schistosomiasis control and provide scientific evidence for control strategies.Methods In accordance with the National Schistosomiasis Surveillance Scheme,schistosomiasis prevalence was monitored in humans,livestock,and snails,and the surveillance data were collected and analyzed statistically.Results In 2009,humans at the surveillance site had positive IHA test results at a rate of 2.6%(20/768) and an infection rate of 0.13%(1/768).However,there were no cases of acute infections or advanced schistosomiasis.The infection rate in livestock was 0.The area of land with snails was 28.5 hm2;17 hm2 of this area had infected snails.The density of living snails was 1.5 snails/plot,and the percentage of plots with snails was 26.24%.The average density of infected snails was 0.002 5 snails/plot,and the rate of snail infection was 0.17%.Conclusion The rate of schistosomiasis infection in residents remains low,and livestock are no longer a major source of schistosomiasis infection at the surveillance site.However,relatively large areas of marshlands have snails and infected snails.Results suggested that,in addition to enhancing snail control,the causes of snail infection in marshland should be investigated and the role and position that various hosts play in the transmission of schistosomiasis should be identified to thus assist in implementing focused control efforts.